The present invention is directed to an electro-mechanical device which makes a keyboard electronic musical instrument such as a electronic organ easier to play. In the standard two manual electronic organ, the lower or accompaniment manual is used for playing chords and bass notes and the upper or solo manual is used for playing the melody. The tone output from a standard organ is sustained in a well-known manner as long as the keys associated with the tone remain depressed. The instant invention is an electro-mechanical memory device for retaining accompaniment keys in the depressed position after the fingers of the instrument player are removed. The note or chord associated with the depressed key or keys is sustained until the instrument player either depresses another accompaniment key or deactivates the entire memory which causes the release of the keys previously held down. The electro-mechanical retention of the keys in the depressed position frees the left hand of the organist for performing other musical functions such as playing on the solo manual. The organist can correlate the tone signal output of the organ with the specific combination of keys held in the depressed position by the electro-mechanical memory and thereby easily determine the note or chord being played. Furthermore, the relationship between the keys forming the various chords can be visually observed by the beginning organist.
The use of a mechanical device to hold down a non-note playing key is well-known in the electronic organ field. Organs made by Hammond Corporation, assignee of the present invention, employ non-note playing preset keys which upon depression by the instrument player are locked in the down position. Such non-note playing preset keys are currently used on a number of Hammond Corporation organs; however, the preset keys are not note playing keys and provide an entirely different and distinct function from the electro-mechanical memory device of the present invention.
A note played on a manual of an electronic organ consists of a fundamental pitch and a number of multiples of the fundamental frequency called harmonics. The combination of fundamental and harmonics available by depressing a playing key on the type of organ having these non-note playing preset keys is controlled by means of draw bars. The draw bars are mounted on the organ console and are movable by the instrument player to provide a mixture of the fundamental and the different harmonics. By adjusting the draw bars to different positions, the instrument player may vary the tone colors available from each playing key. Mounted on the organ console adjacent the lower manual on this type of electronic organ are these plurality of preset keys approximately nine in number which are opposite in color but similar in structural appearance to the playing keys.
Each preset key operates as a switch to make available a different tone color output signal, combination of fundamental frequency and harmonics, in the same manner as the manual adjustment of the draw bars. Each preset key corresponds to a predetermined combination of draw bar positions and depressing a preset key selects a prewired circuit on a panel located inside the organ console which electrically simulates a predetermined combination of draw bars. Only a single preset key is depressed at any one moment and it controls the combination or mix of the fundamental and the various harmonics available when the instrument player depresses the playing keys. Thus the depression of a single preset key automatically provides the instrument player with a prearranged combination of draw bar positions and is a substitute for manually positioning the draw bars. The latching mechanism of the preset keys while retaining a preset key in the depressed position is used by the instrument player for an entirely different function than the present invention.